U.S. patent number 4,902,418 [Application Number 06/927,849] was granted by the patent office on 1990-02-20 for element having a porous wall.
This patent grant is currently assigned to Sulzer Brothers Limited. Invention is credited to Heinrich Ziegler.
United States Patent |
4,902,418 |
Ziegler |
February 20, 1990 |
**Please see images for:
( Certificate of Correction ) ** |
Element having a porous wall
Abstract
The element is disposed in a vessel receiving a fluid flow. The
vessel wall is porous at least for a proportion of the fluid and
bounds an inner chamber communicating through the vessel wall with
a chamber outside the vessel. The element is in the shape of a
plate or tube and is so devised that the porous wall either on its
own or in combination with other similarly shaped elements to form
a module, forms a turbulence generator particularly in the form of
a static mixer for the fluid flow. The resulting turbulence on the
wall of the elements ensures that the wall remains porous.
Inventors: |
Ziegler; Heinrich (Rutschwil,
CH) |
Assignee: |
Sulzer Brothers Limited
(Winterthur, CH)
|
Family
ID: |
4286086 |
Appl.
No.: |
06/927,849 |
Filed: |
November 6, 1986 |
Foreign Application Priority Data
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|
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Nov 22, 1985 [CH] |
|
|
4993/85 |
|
Current U.S.
Class: |
210/321.77;
55/521; 210/321.86; 210/346; 210/433.1; 210/487; 210/489;
210/493.3; 210/493.5; 210/500.41; 261/122.1; 366/337; 366/338;
366/339; 422/48; 422/143 |
Current CPC
Class: |
B01D
63/082 (20130101); B01J 19/32 (20130101); B01D
63/081 (20130101); B01J 4/04 (20130101); B01D
65/08 (20130101); B01F 5/061 (20130101); B01D
29/39 (20130101); B01J 2219/32237 (20130101); B01J
2219/3221 (20130101); B01J 2219/32213 (20130101); B01J
2219/32227 (20130101); B01J 2219/32255 (20130101); B01D
2321/2016 (20130101); B01J 2219/32279 (20130101) |
Current International
Class: |
B01J
4/04 (20060101); B01J 4/00 (20060101); B01J
19/32 (20060101); B01D 65/00 (20060101); B01D
65/08 (20060101); B01D 63/08 (20060101); B01F
5/06 (20060101); B01D 29/39 (20060101); B01D
013/00 (); B01D 025/02 () |
Field of
Search: |
;210/512.1,317,335,336,337,338,340,346,321.86,321.77,446,456,461,486,487,489
;366/336,337,338,339,340 ;137/549,550,808,810,811 ;55/158,521
;422/143,144,48 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2011796 |
|
Jul 1979 |
|
GB |
|
8102683 |
|
Oct 1981 |
|
WO |
|
Other References
Lande et al., "Methods for Increasing the Efficiency of a New
Dialyzer-Membrane Oxygenator", vol. XIV Trans. Amer. Soc. Artif.
Int. Organs, 1968, pp. 227-231..
|
Primary Examiner: Jones; W. Gary
Attorney, Agent or Firm: Kenyon & Kenyon
Claims
What is claimed is:
1. In combination,
a vessel defining a flow path for conducting a fluid flow
therethrough, said vessel having a wall for separating the fluid
flow from the exterior of said vessel; and
at least one element of plate-like cross-section disposed in and
longitudinally of said vessel and shaped to define a corrugated
shape across said flow path for generating turbulence in the fluid
flow within said vessel, said element having an inner chamber of
constant width communicating with said exterior of said vessel
through said vessel wall, a semi-permeable wall bounding said inner
chamber at least in part and being permeable for a proportion of
the fluid flow in said vessel for use in a micron, submicron or
molecular range and a support mesh supporting said semi-permeable
wall thereon.
2. The combination as set forth in claim 1 wherein said
semi-permeable wall has a porosity relative to the fluid flow in
said vessel to filter a proportion thereof into said inner chamber
for passage to said vessel exterior.
3. The combination as set forth in claim 1 wherein said
semi-permeable wall has a porosity relative to the fluid flow in
said vessel to feed a second fluid delivered from said vessel
exterior into said inner chamber into the fluid flow in said
vessel.
4. The combination as set forth in claim 1 wherein said
semi-permeable wall consists of at least one layer of a material to
impart a porosity for use in a microfiltration to ultrafiltration
range.
5. The combination as set forth in claim 4 wherein said layer
material is made of polysulphone and applied or impregnated into a
support of laminated sintered mesh.
6. The combination as set forth in claim 1 wherein said element is
secured to said vessel wall with said inner chamber in direct
communication with said vessel exterior.
7. The combination as set forth in claim 1 which further comprises
at least one tube between said element and said vessel
exterior.
8. The combination as set forth in claim 1 wherein said element
includes a pair of plates extending diametrically across said
vessel and having parallel corrugations to define said inner
chamber therebetween.
9. The combination as set forth in claim 8 comprising a plurality
of said elements defining a module within said vessel.
10. The combination as set forth in claim 8 comprising a plurality
of said elements, each said element being of plate-like
cross-section and of corrugated shape defining a plurality of
corrugations with said corrugations of one element being disposed
transversely of the corrugations of an adjacent element.
11. The combination as set forth in claim 8 comprises a plurality
of said elements, one group of said elements being corrugated and
disposed in parallel and a second group of said elements being
corrugated and disposed in parallel, said second group being
coaxially and angularly disposed to said first group.
12. A filter element comprising
a pair of walls bounding a closed chamber of constant width
therebetween, at least one of said walls being of a porosity to
permit passage of a filtrate from a fluid flow over said at least
one wall into said chamber, said walls being disposed in parallel
relation and in being of undulating shape longitudinally thereof to
define a turbulence generator for the fluid flow passing over said
walls to generate turbulence within the fluid flow;
at least one support mesh supporting each said wall thereon;
and
means in communication with said chamber to conduct the filtrate
from the fluid flow out of said chamber.
13. A filter element as set forth in claim 12 wherein said walls
are shaped to define a wavy shape.
14. A filter element as set forth in claim 12 wherein said porosity
provides for filtration in a microfiltration to ultrafiltration
range.
15. An element comprising
a pair of walls bounding a closed chamber of constant width
therebetween, at least one of said walls being of a porosity
relative to a fluid flow passing over said walls to pass a second
fluid from said chamber into the fluid flow for mixing therewith,
said walls being disposed in parallel relation and in being of
undulating shape longitudinally thereof to define a turbulence
generator for the fluid flow passing over said walls to generate
turbulence within the fluid flow;
at least one support mesh supporting each said wall thereon;
and
means in communication with said chamber to deliver the second
fluid to said chamber.
16. An element as set forth in claim 15 wherein said porosity is in
a microfiltration to ultrafiltration range.
17. In combination,
a vessel defining a flow path for conducting a fluid flow
therethrough, said vessel having a wall for separating the fluid
flow from the exterior of said vessel; and
a plurality of helical elements disposed in said vessel in coaxial
manner to define a turbulence generator for generating turbulence
in the fluid flow, each said element having an inner chamber
communicating with said exterior of said vessel through said vessel
wall, a semi-permeable wall bounding said inner chamber at least in
part and being permeable for a proportion of the fluid flow in said
vessel for use in a micron, submicron or molecular range and a
support mesh supporting said semi permeable wall thereon.
18. In combination,
a vessel defining a flow path for conducting a fluid flow
therethrough, said vessel having a wall for separating the fluid
flow from the exterior of said vessel; and
at least one element disposed in said vessel to define a turbulence
generator for generating turbulence in the fluid flow, each element
including a plurality of layers of contiguous tubes with each said
tube having an inner chamber communicating with said exterior of
said vessel through said vessel wall, a semi-permeable wall
bounding said inner chamber at least in part and being permeable
for a proportion of the fluid flow in said vessel for use in a
micron, submicron or molecular range and a support mesh supporting
said semi permeable wall thereon, said tubes in adjacent layers
being disposed to cross one another with individual tubes having
openings passing therethrough in sealed relation to said inner
chamber thereof to pass the fluid flow.
19. In combination,
a vessel defining a flow path for conducting a fluid flow
therethrough, said vessel having a wall for separating the fluid
flow from the exterior of said vessel; and
a plurality of spaced parallel elements disposed in said vessel and
having vanes extending therebetween in crossing relation to define
a turbulence generator for generating turbulence in the fluid flow,
each said element having an inner chamber communicating with said
exterior of said vessel through said vessel wall, a semi permeable
wall bounding said inner chamber at least in part and being
permeable for a proportion of the fluid flow in said vessel for use
in a micron, submicron or molecular range and a support mesh
supporting said semi permeable wall thereon.
20. In combination,
a vessel defining a flow path for conducting a fluid flow
therethrough, said vessel having a wall for separating the fluid
flow from the exterior of said vessel; and
a plurality of parallel corrugated elements disposed in said vessel
with corrugations thereof in crossing relation to each other to
define a turbulence generator for generating turbulence in the
fluid flow, each said corrugated element having an inner chamber of
constant width communicating with said exterior of said vessel
through said vessel wall, a semi-permeable wall bounding said inner
chamber at least in part and being permeable for a proportion of
the fluid flow in said vessel for use in a micron, submicron or
molecular range and a support mesh supporting said semi permeable
wall thereon.
Description
This invention relates to an element having a porous wall. More
particularly, this invention relates to a filtration element.
As is known, various types of elements have been provided for the
filtration of various fluids. For example, British Pat. No.
2,011,796 describes a filter element which is disposed within a
vessel so as to filter a fluid flow. In this case, the filter
element is formed as a tubular structure with a porous wall through
which a filtrate may pass into an internal chamber for subsequent
removal from the vessel.
One problem which always arises in the filtration of any media or
fluid is to give each individual part of the medium a chance to
expose the filtrate to the filter collecting chamber. That is, the
filter is more efficient as the filter is better able to filter out
all the filterable proportion from a given fluid flow. However,
achieving this state becomes difficult in practical filtration.
Specifically, boundary layers form inside the vessel on the walls
which bound the filtrate collecting chambers and the rate of flow
or the passage of the filtrate in the boundary layers decreases so
that only a small proportion of the through-flowing fluid contacts
the actual porous wall. Further, the removal of the filtrate often
causes an increase in the viscosity of the fluid to be filtered.
This, in turn, adds to or, at least, preserves the boundary
layers.
Heretofore, various attempts have been made to provide an
additional exchange of those zones of the through-flowing fluid
which are near the porous walls, for example, by positioning a
series of wire screens in those zones so as to increase the
turbulence of the fluid flowing over the porous wall. In some
cases, the filter surface has been moved relative to the fluid
flow. Unfortunately, at flow speeds which provide satisfactory
take-up of the filterable proportion, actions of these kind either
consume substantial energy or are of limited effect and also
expensive. These difficulties also occur with various
eddy-producing devices on the porous walls as well as with the
variously known agitators or scraper vanes which have been
operative along the filtration surfaces of a filter or with devices
known generically as static mixers.
By way of example, guide or deflecting surfaces have sometimes been
provided in the flow to a filtration surface in order to produce a
braided or plaited flow after such a surface. In addition, the
filter surface can also be moved across the flow direction of the
treatment material. In many cases, the flow speeds are in the
laminar range. However, it must be possible for the proportion of
that flow which is to be removed by filtration to be in contact
with the filter surface for a sufficiently long time. Braided
flows, on the one hand, decay rapidly and have little effect so far
as the subsequent filter surfaces are concerned. Further, moving
filter surfaces are effective but are technologically very
elaborate.
The range of problems noted above also becomes increasingly
difficult as the filter pore size decreases.
Where turbulence generators have been used to produce eddy currents
in the flow issuing from them, such eddy currents, in the light of
the Reynolds numbers normal in such systems, are sometimes the
characteristic dimensions of the turbulence generator. They
therefore have only a very limited effect as far as filter surfaces
are concerned.
Accordingly, it is an object of the invention to increase the
contact time of the filtrate of a fluid flow with a filter
surface.
It is another object of the invention to remove residues building
up on a porous filter surface during operation in a relatively
efficient manner.
It is another object of the invention to prevent the build-up of
residues on a porous filter surface for a fluid flow.
It is another object of the invention to even out differences in
concentration in a fluid being filtered.
It is another object of the invention to be able to filter a fluid
flow at reduced flow losses and technological outlay.
It is another object of the invention to provide a filter structure
which can be used in processes requiring small to very small pore
sizes in the material to be filtered.
Briefly, the invention provides an element for positioning in a
fluid flow which has an inner chamber and a porous wall bounding
the chamber, at least in part. In addition, the element is of a
shape to define a turbulence generator for generating turbulence
particularly in the form of a static mixer in a fluid flow passing
thereover.
The element may be constructed with a plate-like cross-section, for
example in the form of a lamella, or may have a tubular
cross-section.
The shape of the element may be similar to the shape of a static
mixer element and may be combined with like elements in a static
mixer array.
A filter employing the element may be constructed with a vessel for
a fluid flow wherein a wall of the vessel separates the fluid flow
from the exterior of the vessel. In this case, at least one of the
elements is disposed in the vessel so as to generate turbulence in
the fluid flow while at the same time filtering a filtrate from the
fluid flow through the porous wall into the inner chamber of the
element for subsequent outlet through the wall of the vessel to the
exterior. Alternatively, the element may be used to introduce a
fluid such as a gas into the fluid flow.
The construction of the filter element is such that the element
provides guide or deflecting surfaces in a constructionally unitary
manner. Thus, braided flows which issue from the deflecting
surfaces are operative for the filter surface even as they arise.
Consequently, higher shearing stresses on the filter surfaces are
available than in previously known systems which are disposed after
or before a filter element. Further, the filter surface remains
open and the pores are not restricted by any deposits. Thus, a
thorough mixing of the fluid flow is combined with the exposure of
the filter surface to the various proportions of the fluid
flow.
The filter element may be formed in a corrugated manner so that
wave like surfaces are provided to the fluid flow in order to
increase turbulence in the fluid flow. Because of the geometry of
the element, a continuous reorientation and intensive mixing of a
passing fluid flow occurs in such a manner that the boundary layers
of the fluid near the surfaces of the element are renewed and
replaced by components which tend to move towards the center of the
fluid flow. Thus, a so called plug flow arises.
These and other objects and advantages of the invention will become
more apparent from the following description taken in conjunction
with the accompanying drawings wherein:
FIG. 1 illustrates a cross-sectional view through an element
constructed in accordance with the invention;
FIG. 2 illustrates a cross-sectional view of an element having a
plate or a tubular cross-section in accordance with the
invention;
FIG. 3 illustrates a cross-sectional view of a filter structure
employing a vessel and an element in accordance with the
invention;
FIG. 4 illustrates a part perspective view of a further embodiment
of an element in accordance with the invention;
FIG. 5 illustrates a plan view of a vessel having a corrugated
filter element in accordance with the invention;
FIG. 6 illustrates a view taken on line A--A of FIG. 5;
FIG. 7 illustrates a corrugated element constructed in accordance
with the invention;
FIG. 8 illustrates a cross-sectional view of a vessel containing a
plurality of elements constructed in accordance with the
invention;
FIG. 9 illustrates a cross-sectional view of a different
cross-section of the vessel in FIG. 8;
FIG. 10 illustrates a diagrammatic perspective view of an element
shaped to form a helical static mixer fitted within a vessel in
accordance with the invention;
FIG. 11 illustrates a diagrammatic view of two-shaped elements
combined to form a static mixer in accordance with the
invention;
FIG. 12 illustrates a diagrammatic view of plate-like elements
combined to form a static mixer in accordance with the
invention;
FIG. 13 illustrates a diagrammatic view of corrugated elements
combined to form a static mixer in accordance with the
invention;
FIG. 13a illustrates a view taken on line C--C of FIG. 13; and
FIG. 14 illustrates a view taken on line B--B of FIG. 6.
Referring to FIG. 1, the element is formed of a pair of porous
walls 1 each of which is carried by a support mesh or lattice 19
which defines a closed inner chamber 4. As indicated, the porous
walls 1 form the boundary of the inner chamber 4 and are in
parallel relation to each other. This element has a plate-like
cross-section and is shaped, for example as indicated in FIG. 7, to
define a corrugated or wavy shape which functions as a turbulence
generator 8 for generating turbulence in a fluid flow passing
thereover.
Each porous wall 1 of the element is of a porosity to permit a
proportion, i.e. a filtrate of the fluid flow to pass through into
the inner chamber 4.
Referring to FIG. 2, the element may be constructed with a pair of
porous walls 1, each of which is mounted on a separate support mesh
19 with the inner chamber 4 disposed between the two meshes. As
indicated, each support mesh 19 has a structure which is inherently
pervious. In this regard, the meshes 19 have average apertures
which are at least three times as large as those of the pores of
the walls 1 in order to enable fluid to flow through the walls 1
and into the inner chamber 4.
Of note, the element may be of tubular cross-section wherein the
porous wall 1 is tubular and is mounted on a mesh 19 of tubular
shape.
Referring to FIG. 3, an element constructed with a cross-section as
indicated in FIG. 1 and corrugated in a manner similar to that
shown in FIG. 7, is placed in a vessel 3 having an internal wall 10
to define a path for a fluid flow, as indicated by the arrows 2. As
indicated in FIG. 3, the element is disposed on a diametric plane
of the vessel 3 while being shaped to conform to the cylindrical
interior surface of the vessel 3 along the length of a vessel 3 as
indicated in FIG. 5. The element itself forms a turbulence
generator for the fluid flow 2 so as to generate turbulence within
the flow.
As indicated FIG. 3, the vessel 3 may be disposed in a second tube
22 in spaced concentric relation so that a chamber 5 is disposed
between the vessel 3 and tube 22. Further, a plurality of tubes 11
are connected between an opening in the filter element and an
opening in the wall 10 of the vessel 3 in order to communicate the
inner chamber 4 of the filter element with the chamber 5 exterior
to the vessel 3. In this way, filtrate which passes through the
porous walls 1 of the filter element is able to pass through the
tubes 11 into the chamber 5 for subsequent processing or recycling,
as is known.
Referring to FIG. 6, in an alternative construction, the filter
element may extend through the vessel 3 may have a solid wall with
an inside diameter D1 and an outside diameter D2 and the wall 10 of
the tubular vessel 3 so as to communicate the inner chamber 4 of
the element directly with the chamber 5 exterior to the vessel wall
10.
If the element is to be used as a filter element, the walls 1 are
porous only with respect to the component fluid flow 2 in the
vessel 3 which is to flow through the wall 1 as a filtrate into the
inner chamber 4 for a subsequent flow into the exterior chamber
5.
If the element is used to carry some other fluid, for example, a
gas or a nutrient solution, the wall 1 may have a porosity relative
to the fluid so as to mix this second fluid into the fluid flow 2.
In this case, the element is a mixing element and the gas or
nutrient solution would flow from the exterior chamber 5 into the
inner chamber 4 and thereafter through the porous walls 1 in order
to be mixed into the fluid flow 2 in the vessel 3. In the case of
the embodiment illustrated in FIG. 3, the gas or nutrient solution
would flow from the exterior chamber 5 through the tubes 11 and
into the inner chamber 4 or as in the embodiment of FIG. 6, the gas
or nutrient solution would flow directly from the exterior chamber
5 into the inner chamber of the element.
Each porous wall 1 may consist of at least one layer of a material
of a porosity or of a pore size to impart a porosity for use in a
microfiltration to ultrafiltration range i.e. in a micron,
sub-micron or molecular range. In such a case, the layer may be a
semi-permeable layer in the form of a diaphragm. Further, the layer
of material may be a layer of polysulphone applied to or
impregnated into a laminated sintered support mesh or lattice
19.
In another embodiment, the element may be made with a single porous
wall 1 and a non-porous wall with the inner chamber 4 bounded by
the two walls.
Referring to FIG. 4, the filter element may be held in a frame 13
which extends in seal-tight relation about the inner chamber 4
while a connecting pipe 14 extends through the frame 13 to
communicate the inner chamber 4 with an external chamber.
Referring to FIGS. 8 and 9, a plurality of corrugated elements may
be stacked together in parallel relation so as to define a
plurality of filter chambers for a fluid flow within a vessel 3. In
this case, one group of corrugated elements may be disposed in
parallel while a second group of like elements is coaxially and
angularly disposed, for example at 90.degree., to the first group
as indicated in FIG. 9.
A plurality of a filter elements may be combined to form a module
to provide a turbulence generator which functions as a static mixer
8. For example, as indicated in FIG. 10, a series of elements, each
of which is of helical shape, may be disposed within a tubular
vessel 3 in a coaxial manner. Alternatively, as shown in FIG. 11,
each filter element may be formed as a tube with a plurality of
tubes contiguous to each other to form a layer 16 as illustrated.
In this case, the tubes in the adjacent layers 16 are disposed to
cross one another. Further, the individual tubes may be provided
with openings 12 in the form of slots which pass through the tubes
in sealed relation to the inner chambers so that the fluid flow may
pass directly through the filter elements. As indicated in FIG. 12,
each filter element is in the form of a plate with the walls of
each plate having turbulence producing vanes 21 thereon which act
as guide surfaces for guiding the fluid flow therebetween. Further,
the vanes 21 of adjacent layers cross each other in a transverse
manner. As indicated in FIG. 13, each filter element layer 15 is
corrugated with the corrugations 9 of each layer disposed in
criss-crossing relation to the corrugations 9 of an adjacent layer
15. Further, openings 20 in the form of circular openings are
provided as FIG. 11. In this case, the corrugations 9 of the
respective layers 15 define turbulence producing surfaces.
The arrangements of the filter elements in the static mixer
arrangements in FIGS. 11, 12 and 13 cause repeated deflections of
the fluid flow passing over and through the filter elements. This,
in turn, produces eddy currents which continuously bring more
layers near the porous walls, so that each portion of the fluid
flow has the chance of contacting the porous wall for a
sufficiently long period of time to permit filtrate to pass
through.
One interesting use of the filter elements is in fluidized reactor
technology. In reactors of this kind, particularly in difficult
technical areas such as technologies for the culture of living
cells, turbulence generators are used to maintain a culture bed in
a continuous state of thorough mixing and to make sure that there
is no uncontrollable eddying in the bed and that there is no
repeated mixing together of elements previously separated from one
another. The above described filter elements which inherently form
turbulence generators may be used to carry a fluid from an exterior
chamber in order to gas the fluidized bed. If the porous wall is
appropriately structured, i.e., is provided with an appropriate
porous diaphragm, in situ gassing without bubbling can be provided
in a reactor of this kind.
Referring to FIG. 14, one method of making a filter element such as
illustrated in FIG. 6 may be as follows:
First, the plate-like element is corrugated and then introduced
into a rotatable sleeve of a greater diameter D3 than the diameter
of a subsequently finished vessel D2; the introduction of the
corrugated element being such that the inner chamber is radially
disposed. Next, the sleeve is rotated while a hardenable plastic is
poured into the sleeve in order to form a hardened peripheral tube
having an inside diameter D1 with the element secured therein at
opposite radial ends. After curing or hardening is complete, the
resulting sleeve with the embedded element is then withdrawn from
the sleeve. An outer layer of the fabricated tube is then removed
by grinding or turning so that the inner chamber of the filter
element is exposed at opposite radial ends. In this respect, the
tube is ground or turned down to a diameter D2 as indicated in FIG.
14. This diameter also corresponds to the diameter illustrated in
FIG. 6. Once machined to this state, a unit arises in which the
inner chamber of the element is open to the outside of the tube
(vessel 3 in FIG. 6). This unit can then be inserted into a second
tube having an inner diameter which can be as large as the diameter
D3 indicated in FIG. 14.
The above method may be used with minor modification in order to
produce a filter element as indicated in FIG. 3. However, in this
case, the inner chamber 4 must be sealed off against the fluid flow
2 at the places 17 of the wall 10 of the vessel 3.
The invention thus provides a filter element which has a dual
characteristic of being capable of filtering a fluid flow while
also creating turbulence in the fluid flow. The construction of the
filter element is such that a continuous stimulation or turbulence
is imparted to a fluid flow flowing over the element. In this way,
boundary layers are disturbed during fluid flow in a relatively
simple economical manner without the need for additional
components.
Further, the shape of the filter element creates turbulence
throughout the length of the element without decay of
turbulence.
The element may be used within a vessel to filter a filtrate from a
fluid flow passing through the vessel or to admix fluid or gas from
outside the vessel into the fluid flow. Further, a plurality of
elements may be combined into a module, particularly in the form of
a static mixer for use in the flow path of the fluid of the
vessel.
* * * * *